1. Field of the Invention
The present invention relates to an improved method of storing solar radiation energy in spacecrafts and utilizing it in a highly efficient manner for space propulsion or attitude control thrusters.
2. Prior Art
In outer space, solar radiation is a free source of energy and is widely used for the generation of electricity. Its usefulness for rocket propulsion applications, however, is curtailed because of the following drawbacks: (1) the relatively high cost of solar cells; (2) the relatively low efficiency of these cells, typically in the 10-20% range; (3) the requirement of heavy battery systems for accumulating and storing the electric energy thus generated; and (4) the low efficiency of converting the electric energy into readily available propulsion energy.
A chemical scheme, i.e. the photolysis of chlorine molecules to chlorine atoms has been proposed for the conversion of the solar energy into chemical energy ("Radiation Augmented Propulsion Feasibility", S. C. Hurlock et al, Final Report, AFRPL TR-85-068, Dec. 1985.) However, such a system is impractical in view of the great difficulty of storing chlorine free radicals at a useful pressure without their instant recombination to molecular chlorine and the very low performance of chlorine as an oxidizer in a rocket propulsion system.